Effect Of Gaseous Additives Research Articles

The effects of moisture and gaseous additives on SF6 recovery characteristics

In order to investigate the intrinsic recovery characteristics of SF6 an idealized model-breaker experiment is designed. The experimental simulation of the interruption phenomena offers the possibility to study the evolution of the free-decaying plasma dielectric strength against the recovery time. The effect of gaseous additives such as air, nitrogen and oxygen on the SF6 recovery characteristics has been researched. The obtained recovery curves show distinct phases as for pure SF6. The influence depends on the gaseous additive nature and its proportion to the gaseous mixture. The presence of water vapor (humidity) in the breaking chamber is proved to be a degradation agent of the SF6 insulating and recovery properties. Both dielectric and post-arc recovery studies show that the gas dielectric strength reduces with the increment of the humidity concentration. Copyright © 2005 John Wiley & Sons, Ltd.

Hydrogenation of carbonylic compounds: Part II: The influence of alcohols on the hydrogenation of carbonyl compounds

In this study several metal catalysts have been applied (viz. Pt, Pd, Rh and Ga-promoted Pt) in the reactions of 1-propanol and 2-propanol (in hydrogen). Information obtained in this way is used to elucidate the effects of alcohols ( n- and iso-alcohols) on the hydrogenation of carbonyl compounds over the catalysts mentioned above. Effects of gaseous additives, effects of promoters thereon and, some other effects can be explained by the model suggested by Van der Burg et al. Discussion based on the results obtained by this study and on information from the literature, leads to the conclusion that in hydrogenation of carbonyl compounds the addition of the first hydrogen atom is the most probable rate-determining step.

Scientific principles of synthesis of liquid hydrocarbons from CO and H2 in the presence of cobalt catalysts (review)

The effect of the nature of the support, method of preparation and preliminary treatment of the catalyst (temperature of reduction and heat treatment with air) on the synthesis of liquid hydrocarbons from CO and H2 in the presence of Co catalysts was examined in the present review. The effect of the composition of the starting gas mixture on the occurrence of the process and composition of products formed was demonstrated. Some features of genesis of Co catalysts in different stages of their preparation and the effect of gaseous additives on synthesis were determined. Generalizations were made concerning the features of formation of Co catalysts.

The effect of gaseous additives on the response of the helium ionization detector

Changes in the response of the helium ionization detector which occur when varying amounts of gases are added to the helium carrier gas at different applied voltages have been investigated. The addition of hydrogen, argon, oxygen, or nitrogen to the helium carrier gas causes an increase in the detector response when the voltage applied to the detector is more than 350 V, and a decrease in the detector response when the applied voltage is less than 350 V. It was also found that the detector responds positively and linearly to neon when high concentrations of gaseous additives were added to the helium.

Energy transfer from carbon monoxide flames

Heat fluxes in the vicinity of the reaction zone of carbon monoxide—air flames were measured with a conductivity-type heat-flow meter. It was found that, near the flamefront, the heat flux is much greater than that predicted from ordinary forced convection. Calculations were made by means of a correlation which includes terms for the diffusion and recombination of various labile species present in the flames. The concentrations of atoms and radicals necessary to produce the experimentally determined heat fluxes were estimated and found to be considerably higher than expected from equilibrium considerations. The catalytic effect of different surfaces was examined by coating the probe tip with either platinum or an oxide mixture. The effect of gaseous additives on the heat flux was also studied. Water vapor has a marked effect on the combustion mechanism of carbon monoxide, and drying of the combustible gases reduced the heat flux because of the decrease in concentration of hydrogen atoms. Traces of bromine added to the moist flame produced a similar effect.

72. The effect of gaseous additives on the oxidation of carbon by photolysed carbon dioxide

72. The effect of gaseous additives on the oxidation of carbon by photolysed carbon dioxide

The effect of gaseous additives on the reaction between carbon dioxide and graphite induced by vacuum ultra-violet radiation

The rate at which graphite is gasified on exposure to photolysed (1165 Å and 1236 Å) carbon dioxide is reduced by addition of 0.1 v/o methane. An interpretation is proposed involving the decomposition of methane into methyl and methylene radicals, which subsequently react with the graphite surface. The addition of other sources of methylene or methyl radicals (diazomethane, ketene, azomethane, and acetone) also reduce carbon gasification. Acetylene, ethylene and nitric oxide inhibit oxidation by gas phase scavenging of oxygen atoms.